1. Field of the Invention
This invention pertains generally to trailer hitching aids, and more particularly to an optical guidance system which assists a driver to accurately maneuver a tow vehicle toward a trailer hitch connecting position.
2. Description of the Background Art
Hitching a trailer vehicle to a tow vehicle can be a difficult and time consuming task as the hitching components or other coupling means of the two vehicles are not in view of the driver of the tow vehicle as it is being maneuvered into position for coupling with the trailer. As a result, the driver of the tow vehicle has to back the tow vehicle toward the trailer's hitch by estimating its location and direction relative to the location of the tow hook or ball on the tow vehicle. This requires the driver to repeatedly exit the tow vehicle to check the alignment and distance between the hitching components, which is an inconvenient and time consuming process. Alternatively, the driver may enlist the assistance of another person or "spotter" who is situated outside the tow vehicle to provide directions to the driver as to the appropriate action to align and couple the trailer hitching components. When no other person is available for such assistance, the driver is left to attempt hitching the trailer to the tow vehicle using the time consuming process previously described. Additionally, neither of these methods of hitching a tow vehicle are as accurate or convenient as when the driver receives immediate visual feedback regarding trailer hitch and tow hook alignment while operating the tow vehicle.
Numerous types of trailer hitching aids have been devised, some examples of which range from mechanical linkages between vehicles to proximity sensors with alarms and to targeted light beams. One such system consists of an infrared light detector and two ultrasonic sound detectors mounted on the back of the towing vehicle, and transmitters are mounted on the front of the trailer. This system allows distances and angles to be determined by measuring the velocity differences of the signals, providing the data from the signals into a microcomputer which performs the calculations using a software program. However, the need for a microcomputer running a software program renders this system unnecessarily complex and expensive.
Another system consists of two light emitters mounted on a trailer. One light emitter sends a signal to the back of the towing vehicle. The towing vehicle has several sensors that indicate lateral alignment, and a display is provided in the passenger compartment of the vehicle to give an indication of position. The other light emitter points downward from the hitch and gives an indication of when the hitch is over the ball for coupling. The alignment sensors utilize microelectronic circuits to sense the light beam and to determine its alignment. Unfortunately, the use of the microelectronic circuits wired to the display in the passenger compartment requires extensive installation time and equipment cost.
A third such system uses a single light mounted on the hitch of the trailer and a translucent target mounted on the back of the tow vehicle. The driver looks back at the target when backing up and, when the light hits the "bullseye" portion of the target, the driver knows that the hitch is aligned. The light beam position is initially set up when the trailer hitch is coupled so that the light shines on the "bullseye". The source light mounted atop the trailer hitch increases the obtrusiveness of the system and unnecessarily subjects the light to theft and/or damage.
Accordingly, there exists a need for an easily adaptable and relatively inexpensive vehicle hitching system to assist the driver of a tow vehicle during a trailer hitching process that provides immediate feedback to the driver regarding the alignment and distance off center between the hitching components. The present invention satisfies this need, as well as others, and overcomes the deficiencies found in prior technology.